The present invention relates to image processing systems in general and in particular to a method for conversion of a Color Electronic Pre-press System (CEPS) image data file to a Page Description Language (PDL) file.
It is well known that an image data file prepared on a Color Electronic Pre-press System (CEPS) cannot be exposed on a PostScript-only output device. Generally speaking, the incompatibility between CEPS image data files and PostScript-only output devices derives from the format in which LineWork entries are stored in CEPS image data files as opposed to Continuous Tone image formats which are generally compatible with PostScript-only output devices.
Several approaches have been suggested to convert LineWork files of CEPS run length encoded (RLE) raster formats into PostScript files. One such approach includes the recognition of characters and graphic elements from the CEPS run length encoded (RLE) raster data and their subsequent conversion to equivalent PostScript vector representations. However, this approach suffers from several limitations including that it can handle LW data only and the LW-CT interface is not addressed, it produces complex LW files of linear vectors which typically take a long time to convert and to RIP, it does not produce separated PS files directly, it does not handle HCT data at all, and others. Another approach includes the conversion of a LineWork file and a Continuous Tone file into a single RLE image file which can be handled by a PS Level 2 RIP. However, this approach typically leads to unacceptably long processing times due to data explosion because of the high resolution of raster scanning, typically, in the order of 100 lines per mm.
There is therefore a need for a method for conversion of a Color Electronic Pre-press System (CEPS) image data file to a vector dominated Page Description Language (PDL) file.